I just bought another big boat, so the 6' pickup bed wasn't going to cut it :

So, I started building this on Monday afternoon:

I really like this, just screwed on a 2x4 that I drilled some 1 3/8" holes with the hole saw:

The nice thing is that I built it just high enough that the dirtbike will fit below the yaks, along with coolers, bicycles, etc.

The lumber and a pound of screws cost about 35 bucks. I then bought another 3$ box of screws, 5 foam noodles @ $1.50 each, and a 5$ roll of duct tape ( I think that the rear noodles would get tore up quicker so I just covered it in duct tape)